Convertible fluid operated free pump system



Dec. 10, 1963 c. J. COBERLY 3,113,522

CONVERTIBLE FLUID OPERATED FREE PUMP SYSTEM Filed Dec. 26. 1961 6 Sheets-Sheet 1 HARE/S, mac/1', Russsu. 6: KER/v Dec. 10, 1963 c. J. COBERLY 3,113,522

CONVERTIBLE FLUID OPERATED FREE PUMP SYSTEM Filed Dec. 26, 1961 6 Sheets-Sheet 2 INVENTOE CLARE/v05 J. COBERLY BY H45 ATTORNEY? m2 HARE/S, M501, R0555 &/KER- Dec. 10, 1963 c. J. COBERLY 3,113,522

CONVERTIBLE FLUID OPERATED FREE PUMP SYSTEM Filed Dec. 26. 1961 6 Sheets-Sheet 3 55 FIG. 3.

INVENTOR.

CLARENCE J. COBERLY 5y H/S Arrow/Em HARE/5, A7501, Rosseu. & KERN Dec. 10, 1963 c. J. COBERLY 3,113,522

CONVERTIBLE FLUID OPERATED FREE PUMP SYSTEM Filed Dec. 26. 1961 6 Sheets-Sheet 4 IN VEA/ 7'02 [LARENCE J COBERLY 8! 6 /5 ATTORNEYS Maze/5, Mac/ 4 RussELL & KER/v United States Patent 3,113,522 CGNVERT'EBLE @PERATED FREE PUM? SYSEEM Clarence .l'. Ccherly, San Marine, Calif, assigner to gobs, line, Huntington Park, Calif., a corporation of alifornia Filed Dec. 26, 1963., Ser. N l62,(i6 19 (Claims. (Cl. 103-46) The present invention relates in general to a fluid operated pump system for oil wells, and a general object is to provide a system which is readily convertible from one type of pump to another, e.g., to meet changing well conditions, with no change in the tubing system initially installed in the well. Thus, the system may be converted from one type of fluid operated pump to another without an expensive pulling job.

Basically, the present invention contemplates a fluid operated pump of the reciprocating type which, as disclosed, for example, in my Patent No. 2,949,857, granted August 23, 1960, is divided into two separate units independently installable in and removable from the well. One unit is a pump unit comprising fluid operated engine means and pump means actuable by the engine means. The other is an engine valve unit comprising fluid operated engine valve means for controlling the operation of the engine means, i.e., for controlling the magnitudes and directions of fluid pressure diflerentials applied to engine piston means forming part of the engine means.

As disclosed in the aforementioned patent, the pump and valve units may be independently, or simultaneously, run into and out of the well through pump and valve tubings, the former preferably being a production tubing for conveying fluid produced by the well to the surface, and the latter preferably being a supply tubing for conveying operating fluid, such as clean crude oil, downwardly to the fluid operated pump. The production and supply tubings are connected at their lower ends to a bottom hole assembly which includes pump-unit and valve-unit housings providing therein pump-unit and valve-unit chambers for receiving the pump and valve units, respectively, when they are in their operating posi-. tions, the pump-unit and the valve-unit chambers being aligned with the production and supply tubings, respectively.

An important object of the invention is to provide a fluid operated pump system of the foregoing nature capable of accepting fluid operated pump units of different types to meet difierent well conditions, and capable of accepting correspondingly different engine valve units, all without any necessity for pulling the tubing system from the well. For example, the pump unit may comprise one, preferably single acting, fluid operated pumping device, or it may comprise two, preferably single acting, fluid operated pumping devices. In the first instance, the engine valve unit comprises a single engine valve means and, in the second, duplex arrangement, it comprises two engine valve means. While the two pumping devices, and their respective engine valve means, may operate independently of each other, they preferably operate in timed or phased relation, as disclosed, for example, in my Patent No. 2,939,397, granted June 7, 1960.

In order to accommodate different pump unit and engine valve unit combinations, such as the foregoing, the invention contemplates, and an important object thereof is to provide, corresponding crossover or passage units which are installable in and removable from the well independently of, or simultaneously with, the corresponding pump and valve units, and each of which includes passages necessary to provide the proper fluid interconnections between the pump unit and the valve unit cor- Patented Dec. 10, 1%63 responding thereto. Thus, with this construction, all that is required to convert from one type of fluid operated pump to another is to remove the pump, valve and passage units and replace them with a new set, which is an important feature of the invention.

Another object of importance is to provide a fluid operated pump system wherein the passage unit is also hydraulically installable and removable, through a third tubing which is connected at its lower end to the bottom hole assembly in alignment with a passage-unit chamber in a passage-unit housing forming part of the bottom hole assembly. Another object in this connection is to utilize the third tubing as a return tubing for conveying spent operating fluid to the surface,- thereby providing a closed system insofar as the operating fluid is concerned.

Another object is to provide a construction wherein the pump-unit chamber, the valve-unit chamber and the passage-unit chamber are all located side-by-side in lat erally spaced relation to minimize the lengths of the flow paths between the pump, valve and passage units when they are in their operating positions in their respective chambers.

Considering some more specific objects of the invention, one is to provide a duplex pump wherein the pump unit includes two axially, i.e., vertically, aligned and spaced fluid operated pumping devices, wherein the engine valve unit comprises two axially aligned and spaced engine valve means, and wherein the passage unit has correspond ing axially aligned and spaced components.

Another specific object is to provide a single acting duplex pump made up of tWo standard single acting pumping devices and two standard, complementary engine valve means with no major structural change This permits standard parts to be used for the pump and engine valve units, which is an important feature.

A further specific object is to provide a duplex-pump passage unit which includes two axially aligned, passaged heads which are spaced apart by an interconnecting sleeve and certain of the passages of which are interconnected by tubes nested within the sleeve.

Still another specific object is to provide a bottom hole assembly wherein the pump-unit, valve-unit and passageunit housings respectively include pump-unit, valve-unit and passage-unit shoes or shoe means interlocked in laterally abutting relation by a tongue and groove connection which includes an undercut, e.g., dovetail, groove in one of the shoe means, preferably the pump-unit shoe means, receiving a complementary tongue on the other shoe means. Another object in this connection is to provide the grooved shoe means with a removable portion having thereon one side wall of the undercut groove, this construction facilitating assembly and disassembly of the set of shoe means.

With the foregoing interlocked shoe or shoe means construction, complex sets of passages may be formed and interconnected readily, which is an important feature.

The foregoing objects, advantages, features and results of the present invention, together with various other objects, advantages, features and results thereof will be evident to those skilled in the fluid operated pump art in the light of this disclosure, may be achieved with the exemplary embodiments of the invention described in detail hereinafter and illustrated in the accompanying drawings, in which:

FIG. 1 is a diagnammatic view illustrating a fluid operated duplex pump system which embodies the invention;

FIG. 2 is a view similar to FIG. 1, but showing various parts in different operating positions;

FIG. 3 is a view similar to FIG. 1, but showing a fluid operated single pump system of the invention, the same tubing system being used for both the duplex and single pump systems;

FIG. 4 is a vertical sectional view on a reduced scale showing a fluid operated duplex pump system of the invention installed in a well;

FIG. 5 is an enlarged, transverse sectional view taken along the arrowed line 55 of HG. 4;

FIG. 6 is an enlarged, transverse sectional view taken along either of the arrowed lines '66 of FIG. 4;

FIG. 7 is "an enlarged, fragmentary side elevational view taken as indicated by the arrowed line 7-7 of FIG. 4, the line along which FIG. 6 is taken also being indicated in FIG. 7;

FIG. 8 is a fragmentary vertical sectional view taken along the larrowed line 8-43 of BIG. 7;

FIGS. 9 and 10 are transverse sectional views respectively taken along the arrowed lines 99 and i1ii10 of BIG. 8;

(FIG. 11 is a transverse sectional view on an enlarged scale taken along the arrowed line 111l of FIG. 4;

FIG. 12 is an enlarged, fragmentary side eleuationail View taken as indicated by the arrowed line 12-42 of FIG. 4, the line along which tF-IG. 11 is taken also being shown in FIG. 12;

'FIG. 13 is an enlarged, fragmentary vertical sectional view showing the upper end of an engine valve unit of the invention, FIG. 13 being an upward continuation of FIG. 14; and

FIG. 14 is a dovmwvard continuation of FIG. 13 and is taken as indicated by the arrowed line 14-14 of FIG. 7.

GENERAL lThC convertible fluid operated free pump system of the invention is illustrated in the drawings as comprising either a duplex pump, consisting of two single acting pumping devices, or a single pump, consisting of one single acting pumping device. However, it will be understood that other constructions fall within the scope of the invention and that the two mentioned are exemplary only.

A semidiagrammatic embodimentZZ of the duplex pump or pump system of the invention is illustrated in FIGS. 1 and 2 of the drawings, while a semidiagrammatic embodiment 244 of the single pump or pump system is illustrated in FIG. 3 thereof. in FIGS. 4 to 14 of the drawings is shown an actual physical embodiment 26 of the duplex pump 22 of FIGS. 1 and 2. Many components are common to the three embodiments 22, 24 and 26 and such components will be identified by the same reference numerals throughout the drawings.

Also, many of the components of the pump embodi ments 2 2, 24 and 26 are structurally and operationally identical to, or at least very similar to, corresponding components of the pump embodiments disclosed in the aforementioned patents. Consequently, to avoid unnec essary duplication, such components will be described only briefly herein, attention being directed to the patents mentioned, which are incorporated herein by reference, fior full descriptions thereof.

Duplex Pump 22 Referring to FIGS. 1 and 2 of the drawings, the duplex pump 22 illustrated therein includes a duplex, single acting, fluid operated pump unit 32, a duplex, fluid operated, engine valve unit 34 for controlling the pump unit, and a complementary passage unit 36 for interconnecting the pump unit and the valve unit in fluid communication.

When in their respective opera-ting positions, the pump, valve and passage units 32, 34- and 36 are disposed in a well in laterally spaced, si'de-by-side relation in laterally spaced, side-by-side, pump-unit, valve-unit and passageunit chambers 4-2, 44 and 46, respectively, being seated on pump-unit, valve-unit and passage unit seats 52, 54 and '56, respectively.

The pump-unit, valve-unit and passage-unit chambers 42, 44 and 46 are. respectively formed in pump-unit, valve-unit and passageaunit housings 62, 64 and 66 colilectively constituting a bottom hole assembly 7Q. In FdGS. l and 2 of the drawings, the housings 62, 64 and 66 are shown as integral for convenience of illustration. However, they are actually independent housings interconnected in a novel manner which will be described hereinafter in connection with the actual physical embodiment 26 of FIGS. 4 to 14 of the drawings.

The pump, valve and passage units 32, 34 and 36 are hydraulically movable between the surface and their operating positions in the respective pumpamit, valve-unit and passageaunit chambers 42, 44 and 46 through tubings 72, 74 and 76, respectively. The tubings 72, 74 and 76 are disposed in laterally spaced, side-by-side relation, being aligned with and communicating at their lower ends with the respective pump-unit, valve-unit and passage-unit chambers 42, 44 and -46. Although shown as integral with the bottom hole assembly 70 in FIGS. 1 and 2 of the drawings for convenience of illustration, the tubings 7.2, 74 and 76 are actually separate elements connected to the pump unit, valve-unit and passage-unit housings 62, 64 and 66, respectively, in the manner shown in FIGS. 4 to 14 of the drawings.

The pump unit 32 is the largest of the units 32, 34 and 36 and, correspondingly, the tubing 72 is the largest of the tubings 72, 74 and 76. In order to provide a large flow capacity for the production fluid produced by the well with a minimum of frictional resistance, the largest tubing 72 is utilized as the production tubing of the system. Preferably, the tubing 74 through which the valve unit 34 is movable is the supply tubing for delivering operating fluid under pressure to the duplex pump 22. The tubing 76, through which the passage unit 36 is movable, serves as a return tubing for conveying spent operating fluid to the surface. Thus, the tubing system is a closed one.

The duplex pump unit 32 includes two axially aligned, interconnected, single acting, fluid operated pumping dcvices 82a and $21). The pumping devices 82a and 82b provide fluid operated engine means and pump means actuable by the respective engine means. More particularly, the pumping devices 8211 and 32b respectively include combined engine and pump pistons or piston means 34a and 3411. These pistons respectively include plungers 36a and 55b reciprocable in cylinders 38a and 88b, and include rods Mia and 90!: respectively connecting the plungers 86a and 86b to plungers 92a and 92b reciprocable in cylinders 94a and 94b. The rods 9% and as!) are axially slidable in annular plugs 96:: and 9612, respectively, carried by the bodies of the pumping devices 82a and 825. When the pump unit 32 is in its operating position, the annular plugs 96a and 96b respectively register with sealing collars Si n and 93b carried by the pump-unit housing 62.

The pistons 34a and 8412 are provided therethrough with axial passages 100a and will: for fluid being pumped from a well fluid inlet 102 at the lower end of the pumpunit housing 62 into the production tubing 72. The passages liltla and ltlllb are connected in series and reverse flow therethrough is prevented by Working valves 104a and 164b, respectively. The well fluid inlet 102 is provided with a standing valve 1dr: which is closed only when the pumping devices 82a and 32b are not in opera tion. During normal operation, the pumping devices 8211 and 82b operate in phased or timed relation, with overlap, so that at least one of them is pumping at all times. Under such conditions, the standing valve 166 remains. open constantly.

The duplex valve unit 34 includes two axially aligned, fluid operated engine valve means 112:: and 11212 for controlling the operation of the engine means of the respective pumping devices 82a and 32b, i.e., for controlling the magnitudes and directions of fluid pressure differentials applied to the respective pistons 84a and 84b. The engine valve means 112a and 1121: respectively include differential area engine valves 114a and 114th axially slidable in engine valve bodies 116a and 11619. When the valve unit 34 is in its operating position in its chamber 44, the valve bodies 116a and l16b respectively register with sealing collars 118a and 11% carried by the valve-unit housing 64-.

The two engine valve means 112:: and 1121) are similar to those fully described in my aforementioned patents, particular attention being directed to my Patent No. 2,939,397. Consequently, a detailed description thereof herein is not necessary.

Considering in a general Way the interrelationship between the pumping devices 8211 and 32b and the engine valve means 112a and 1121), the directions of movement of the pistons 84a and 8412 are, of course, controlled by the respective engine valves 114a and 114b, The piston Sea controls the initial upward movement of the engine valve 114b, while the piston 84!) controls the initial upward movement of the engine valve 1145a. The engine valve 11% controls the initial downward movement of the engine valve 114a, and the engine valve 114a controls the initial downward movement of the engine valve 114]). Preferably, the engine valves 114a and llb have three diilerent speeds in each direction, and each controls its own second and third speeds, as disclosed, for example,

my Patent No. 2,949,857.

The foregoing general interrelationship between the pumping devices 82a and 82b and the engine valve means 12a and 11217 is not, per se, part of the present invention, and is quite similar to that described in complete detail in my Patent No. 2,939,397. Consequently, a detailed description herein will not be necessary, attention being directed to the patent just mentioned for further details.

Sutlice it to state that the desired functional interrelationship of the pumping devices 82a and 82b and the engine valve means 112a and llZb is achieved by means of a system of passages formed partially in the pumping devices and engine valve means themselves, partially in the pump-unit, valve-unit and passage-unit housings 62, 64 and 65, and partially in the passage unit 36. This systern of passages, and the role that the passage unit 36 plays therein, will now be desc ibed.

The aforementioned passage system is designated generally by the numeral 129 and includes corresponding passages 12242 and 12212 for constantly delivering operating fluid under pressure in the supply tubing 74 from the valve unit chamber 44- to the under sides of the plungers 35a and 86b, respectively. (As described in detail in my aforementioned patents, this results in upward movement of the pistons 84:: and 8412 when the pressure in the return tubing 76 acts on the upper sides of the plungers 532a and 92b, the pistons being moved downwardly when the operating fluid pressure in the supply tubing '74 is applied to the upper sides of the plungers 92a and 92b. The reason for the latter is that the areas of the upper sides of the plungers 92a and 92b are very slightly larger than the areas of the lower sides of the plungers 86a and 36b). The passage 122:: extends from the valve-unit chamber 44 at a point above the valve unit 34 to the cylinder 83a below the plunger 85a through the bottom hole assembly 7%, the sealing collar 98a, and the annular plug 95a. Correspondingly, the passage 122b is formed in the bottom hole assembly 7%, the sealing collar 98b, and the plug see. The passage 122% receives operating fluid under pressure from the valve-unit chamber 44- above the valve unit 34 by way of a passage 124a in the sealing collar 118a (the sealing collar 11% having a corresponding passage 12%), and an annular clearance 126 between the valve unit 34 and the valve-unit chamber 44, such annular clearance extending axially from the sealing collar 118a to the sealing collar 11 b.

The passage system 128 also includes passages 128a and 12812 connecting the respective engine valve means 312a and 11212 to the respective cylinders 94a and 941) above the respective plungers 92a and $212. (The pressures in the supply and return tubings '74 and '76 are alternately applied to the upper sides of the plungers 92 and 92b through the passages 128a and 12% to produce alternate downward and upward movements of the pistons 34a and 8 51), as explained in more detail in my aforementioned patents. The return-tubing pressure is obtained by way of passages 12% and 12% in a manner which will become apparent.) The passages 128a and 1238b respectively extend through the sealing collars 118a and 118b, the bottom hole assembly 7%, the sealing collars 955a and 98b, and the plugs 96:: and 961).

It Will be noted that the foregoing passages of the passage system llZd are independent of the passage unit 36. This unit will now be described to provide the foundation necessary for a subsequent description of the passages of the passage system 129 which are related to the passage unit.

The passage unit 36 includes two axially aligned, passaged heads 13th: and lf'iilb respectively laterally opposite the pumping devices 82a and 82b and respectively laterally opposite the engine valve means 1113a and 1125. The heads 1335a and 13% respectively register with sealing collars 132a and 1352b carried by the passage-unit housing 66.

The two heads 1359a and 13% of the passage unit 36 are interconnected and axially spaced apart by an outer sleeve 134. Nested within this sleeve are parallel tubes 136, 138, 149 and 142, these tubes being suitably secured at their ends to the respective heads 13% and Bil/'1, and communicating at their respective ends with hereinafterdescribed passages in the heads 139a and 13%.

As hereinbefore indicated, the passage system 1249 includes passages which interconnect the pumping devices 82a and 82b and the engine valve means 112a and H25 and which pass through the passage unit 36, these being control passages which provide the desired phased, overlapped operation of the pumping devices. Thus, the passage system llZil includes control passages 144a and 14415 which extend from the pumping devices 82a and 82b to the engine valve means 112]) and 112a, respectively, and which include as parts thereof the tubes 136 and 142, respectively. More particularly, the control passage 144a, starting at the engine valve means 112b, extends through the sealing collar 118b, the bottom hole assembly 7%, the sealing collar 132b, the head 13012 of the passage unit 36, the tube 136 of the passage unit, the head 130a of the passage unit, the sealing collar 132a, the bottom hole assembly 7 0, the sealing collar 98a, and the plug Qda. Within the plug 96a, the control passage 144a has a branch 146a adapted to be connected to the cylinder 83a below the plunger 86a by a groove 148a in the rod NM, and has a branch 15% communicating through a restrictor 152a with the cylinder il la above the plunger 9242. Similarly, starting with the engine valve means 11241, the control passage 14% extends through the sealing collar 118a, the bottom hole assembly 7%, the sealing collar 1132a, the head 130a of the passage unit an, the tube 142 of the passage unit, the head 13% of the passage unit, the bottom hole assembly 76, the sealing collar 93:), and the plug 96b. Also similarly, the control passage 14 th is provided Within the plug 961) with a branch 14% connectible by a groove 14811 in the rod b with the cylinder 33b below the plunger 86b, and is provided with a branch l'Etlb communicating through a restrictor 15212 with the cylinder 94b above the plunger 92b.

The passage system 129 also includes control passages 154a and 15% respectively connecting the pumping devices 32a and 82b to the engine valve means @121) and 112a, and respectively including as parts thereof the tubes 13% and 14d of the passage unit 36. It is thought that the paths followed by the control passages 154a and llS-lb may be traced readily Without further description, except to point out that they communicate within the plugs 6a and 9612, respectively with the branches Ella and 15%, respectively, of the control passages 144a and 1445, respectively, through check valves 156a and 156b, re-

spectively. The check valves 156a and 156k prevent flow from the pumping devices 82a and 32b to the engine valve means 112!) and 1120, respectively, but permit reversed flow.

As previously suggested, and as will be clear from the full description appearing in my Patent No. 2,939,397, the control passages 144a, 144b, 154a and 154i; interconnect the pumping devices 82a and 82b and the engine valve means 112a and 11% in such a manner as to produce the desired phase, overlapped operation of the pumping devices. This, per se, forms no part of the present invention. 50 that a further description is not required herein.

It might be well to point out at this stage of the description that there are two additional control passages 16th: and 16% extending from the pumping devices 8201 and 32.5, respectively, and communicating with the return tubing 76. More particularly, starting with the pumping devices 32a and 821), the control passages 169a and Tell]; respectively extend through the sealing collars 93a and 98b, the bottom hole assembly 7% and the sealing collars 132a and 1325. At their ends, the control passages 169a and 16% communicate with the passages 12% and 129b, respectively. All four passages 129a, 129b, 169a and 16% constantly communicate with the return tubing 7 6 through longitudinal passages 162a and 1162b in the sealing collars 132a and 132b, respectively, and an annular clearance 164 around the passage unit 36 between these two sealing collars. Thus, the pass-ages 129a and 12% constantly supply fluid at the pressure in the return tubing 76 to the two engine valve means 112a and 1.1217. The control passages 160a and 160b, however, are blocked at the pumping devices 32a and 82b by the plugs 96a and 96b in the duplex pump 22. Thus, the control passages 160:: and 16Gb have no function in the duplex pump 22. One or the other of them is, however, used in connection with the single pump 24 to be described hereinafter.

Operation of Duplex Pump 22 Since the operational relationship between the pumping devices 82a and 82b and the engine valve means 112a and 11% does not, per se, constitute any part of the present invention, it will not be considered further herein. Instead, this section of the present specification will be devoted to describing the manner in which the pump and valve units 32 and 34, and the passage unit 36 for interconnecting the pump and valve units in fluid communication, are installed and removed. As will be apparent, the

present invention involves three free units adapted to be I hydraulically installed and removed, these being the pump, valve and passage units 32, 34 and 36. These three free units may be installed and removed by means of various combinations of operations, the principal ones of which will now be considered.

One possibility is to install the pump unit 32 without having the valve and passage units 34 and 36 in place. This is done by inserting the pump unit 32 into the upper end of the production tubing 72, closing the upper end of the production tubing, and then directing operating fluid under pressure into the production tubing above the pump unit. Consequently, the pump unit 32 is circulated downwardly into its operating position in the pump-unit chamber 42. At least one of the supply and return tubings '74- and 7 6 is left open as the pump unit 32 is circulated in to permit the pump unit to displace the fluid therebeneath. Preferably, both the supply and return tubings 74 and 76 are left open to reduce fluid friction and permit a higher installation rate.

The pump unit 32 may also be installed with the valve and passage units 34 and 36 already in place, the general procedure being the same as the foregoing. In this case, fluid friction is higher since fewer of the interconnecting passages between the pump-unit chamber 4-2 and the valveunit and passage-unit chambers 44- and 46 are open. When the pump unit 32 reaches the sealing collar 98a,

the flow of fluid from beneath the pump unit 32 by way of the passage 122:: is cut off. Similarly, when the pump unit 32 encounters the sealing collar 9812, the fluid beneath the pump unit can no longer escape through the passage 1221;, the annular clearance 126 and the passage 124a. From this point on, the fluid beneath the pump unit 32 escapes through a passage 167 in the bottom hole assembly 7 0, an annular clearance 169 around the lower end of the valve unit 34, the passage 1241), the annular clearance 126, and the passage 124a, and also escapes through a passage 168 in the bottom hole assembly 70, an annular clearance 170 around the lower end of the passage unit 36, the passage 162b, the annular clearance 164, and the passage 162a. The passage 168 permits the final increment of movement necessary to enable the pump unit 32 to engage its seat 52.

It will be understood that, in a similar manner, the pump unit 32 can be installed with only the valve unit 34 in place, or with only the passage unit 36 in place.

The passage unit 36 may be installed either with or Without the pump and valve units 32 and 34 in place. When neither is in place, the fluid beneath the passage unit 36 is displaced upwardly through both the production and return tubings 72 and 76 in an obvious manner.

If the valve unit 34 is in place when the passage unit 36 is installed, the fluid beneath the passage unit is displaced upwardly through the production tubing 72 only since the valve unit blocks displacement into the supply tubing 7 4. The fluid displacement necessary to permit the final downward movement of the passage unit 36 into engagement with its seat $6 takes place through the passage 16% and a passage 172 in the bottom hole as sembly 7h. The fluid displacement necessary for the final small increment of downward movement of the passage unit 36 takes place through the passage 172.

When installing the passage unit 36 with both the pump and valve units 32 and 34 in place, all of the fluid beneath the passage unit must be displaced through the passage 172, all other interconnecting passages being blocked by the pump and valve units. The fluid displaced through the passage 172 escapes upwardly into the production tubing 72 through the working valves 104a and 104b of the pumping devices 32a and 82b.

The valve unit may be installed either with or Without the pump and passage units 32 and 36 in place. If neither is in place, the fluid displaced by the valve unit escapes into the production and return tubings 72 and 76 in an obvious manner.

If the passage unit 36 is in place as the valve unit 34 is installed, the displaced fluid can escape into the production tubing 72 through various avenues. The fluid displacement necessary for the final increment of downward movement of the valve unit 34 into engagement with its seat 54 takes place through a passage 174 in the bottom hole assembly 7%. This passage communicates with the return tubing 76 through the annular clearance 170, the passage 162b, the annular clearance 164 and the passage 162a. It also communicates with the pump-unit chamber 42, and thus the production tubing 72, through the passage I 58. if the pump unit 32 is in place when the valve unit 34 is installed, the passage 163 is blocked, and all of the displaced fluid must escape into the return tubing 76 in the manner indicated.

The usual sequence in installing the pump, valve and passage units 32, 34 and 36 is to run in the passage unit first, the pump unit next, and the valve unit last.

The pump, valve and passage units 32, 34 and 36 are removed by means of procedures which are essentially the reverse of the foregoing. The principal removal procedures will now be considered.

The valve unit 34, which is likely to require replacement or repair more often than the pump unit 32, can be removed without disturbing either the pump unit or the passage unit 36. This is done by closing the upper end of the production tubing '72, opening the supply tubing 74, and applying pressure to the return tubing 76. The

pressure in the return tubing 76 is applied to the lower end of the valve unit 34 through the passage 162a, the clearance 164, the passage 1 62b, the clearance 17%), and the passage 174. Thus, the valve unit 34 is unseated and circulated to the surface through the supply tubing 74.

If the pump unit 32 is not in place, the valve unit 34 is preferably removed by pressurizing the production tubing 72, at the same time closing the upper end of the return tubing 76 and leaving the supply tubing 74 open. Under these conditions, pressure is applied beneath the valve unit 34- through the passages 168 and 174. Once the valve unit 34 clears its sealing collars 118a and 11812, additional fluid passages are opened to produce a relatively high removal speed with this procedure.

it should be pointed out that, when removing the valve unit 3 with the pump unit 32 removed, some fluid escapes from the production tubing 72 into the supply tubing '74 above the valve unit by way of the passages 122a and 1221;. Consequently, fluid must be introduced into the roduction tubing 72 at a rate high enough to ofiset the loss through the passages 122a and 1122b so as to insure the application of a pressure force to the lower end of the valve unit 34 suflicient to unseat it. In the event that the valve unit 34 is stuck, it might be necessary to install the pump unit 32 first, thereby blocking the passages 122a and 122b, and making the valve-unit removal procedure the same as hereinbefore described for the case in which the pump unit is in place.

The pump unit 32 may be removed without disturbing the valve and passage units 34 and 36 by closing the upper end of the supply tubing 74, opening the upper end of the production tubing 72, and pressurizing the return tubing 76. This applies pressure to the lower end of the pump unit 32 through the passage 162a, the annular clearance 164, the passage 162b, the annular clearance 176 and the passage 168. If desired, both the supply and return tubing 74 and 76 may be pressurized in removing the pump unit 32 with the valve and passage units 34 and 36 in place. However, no flow from the supply tubing 74 will occur until the pump unit clears the passage 1122b. The pump unit 32 is provided at its upper end with a packer means 3.66 of conventional construction (see FIG. 4) which prevents bypassing of the pump unit by the fluid introduced therebeneath as the pump unit is circulated up the production tubing 72.

In the event that the pump and valve units 32 and 34 both require replacement or repair, both may be removed simultaneously without disturbing the passage unit 36. This is accomplished by first unseating the pump unit 32 with the upper end of the supply tubing 74 closed, and then unseating the valve unit 34 with the upper end of the production tubing 72 closed, the necessary pressure being applied through the return tubing 76 in both instances. As soon as the pump and valve units 32 and 34 have been unseated in this manner, the upper ends of the production and supply tubings 72. and 74 are opened and fluid is introduced into the return tubing 76. The pump and valve units 32. and 34 will normally move upwardly at different speeds, but as soon as one of them reaches the surface, all of the flow down the return tubing 76 is available to speed up the removal rate of the lagging unit.

The passage unit 36 may be removed with or without the valve unit 34 in place, but it is necessary to first remove the pump unit 32. The production tubing 72 is then pressurized with the return tubing '76 open and the supply tubing 74 closed. This applies pressure to the lower end of the passage unit 36 through the passage 172. However, bypassing flow from the production tubing '72 to the return tubing 76 is possible through the passage the clearance 170, the passage 162b, the clearance 164, and the passage 162a. Consequently, the pressure in the production tubing 72 must be maintained sufllciently high to oflset the loss through this bypass. However, if the passage unit 36 has been in place for a long time, it may become stuck and impossible to unseat in the manner just described. Under such conditions, a dummy pump unit, not shown, may be run in first, such dummy pump unit being designed to block the passage 168, but having therethrough a passage permitting the entry of fluid into the passage 11.72. Alternatively, the pump unit 32 could serve as such a dummy pump unit by removing the working valves 1434a and 16411.

The valve and passage units 34 and as may be removed simultaneously by first removing the pump unit 32 and unseating the passage unit 36 in the manner described above. Then, the valve unit 34 is unseated as previously described. With both the valve and passage units 34 and 36 unseated, and with the supply and return tubings 74 and 76 open, fluid is introduced through the production tubing 72 to circulate the valve and passage units to the surface. These units are preferably of the same diameter and will, therefore, be circulated to the surface at substantially the same rates. Any diflierence, however, is unimportant since once one of these units reaches the surface, all of the circulating fluid flow is available to speed up the lagging unit.

The foregoing completes the description of the structure and operation of the duplex pump 22. The single pump embodiment 24 of FIG. 3 will be considered next.

Single Pump 24 Turning to FIG. 3 of the drawings, the same bottom hole assembly and the same production, supply and return tubings 72, 74 and 76 are used in conjunction with the single pump 24. Also, the sealing collars 8a, 98b, 118a, 118b, 132a and 132!) are the same.

The single pump 24 includes pump, valve and passage units 232, 234 and 235 respectively corresponding to the pump, valve and passage units 32, 34 and 36. The pump unit 232 differs principally in that it includes but a single pumping device 238, and the valve unit 234 similarly differs primarily in including only a single engine valve means 24%. The passage unit 236 is correspondingly simplified since it is required only to interconnect the single pump device 238 and the single engine valve means 24b.

in the particular construction illustrated in FIG. 3 of the drawings, the pumping device 238 and the engine valve means 240 respectively occupy the positions occupied by the pumping device 82a and the engine valve means 112a. Similarly, the passage unit 236 is provided with a passaged portion corresponding in position to the head 13% of the passage unit 36. If desired, the pumping device 238 and the engine valve means 249 could occupy the positions of the pumping device 82b and the engine valve means 112b, the passaged portion of the passage unit 236 being similarly relocated.

The pump, valve and passage units 232, 234 and 236 respectively include dummy extensions 242, 244 and 246 which respectively block the passages in the sealing collars 98b, 118k and 1322). Thus, only the sealing collars 98a, 118a and 132a are operative.

Considering the pump unit 232 in more detail, since it incorporates only the one pumping device 238, and since this pumping device is single acting, it is necessary to provide it with a standing valve 248 at its upper end. In most other respects, the pumping device 238 is substantially identical to the pumping devices 82a and 82b. For convenience, the parts of the pumping device 238 will be identified by the same reference numerals used for the corresponding parts or the pumping device $241, and the differences will be pointed out.

One difference in the pumping device 238 over the pumping device 82a is that the branch 15% of the passage 144a, and its restrictor 152a, are omitted, only the branch 146a being used. Also, the check valve 156a is omitted from the passage 154a, and the latter extends radially all the way through the annular plug %a. Instead of the single control groove 148a, the rod 943a of the piston 84a is provided with two control grooves 250 and 252. The former connects the operating fluid under pressure in the cylinder Silt: above the plug 96a to the branch passage 146a as the piston 34a approaches the end of its downward, return stroke. The control groove 252 connects the passage 154a to an extension 254 of the passage 1686: as the piston 84a approaches the end of its upward, working stroke. it will be recalled that the passage 150a was blanked oil and not used in the duplex pump 22. However, it is used in the single pump 24, being in communication with the extension 254.

The engine valve means 246 is similar to the engine valve means 112a and no further description is necessary herein.

The passage unit 236 is provided simply with two passages 256 and 258 the first of which interconnects the portion of the passage 144a leading to the pumping device 238 and the portion of the passage 154i; leading to the engine valve means 246. The passage S interconnects the portion of the passage 154a leading to the pumping device 238 and the portion of the passage 144b leading to the engine valve means 240.

Operation of Single Pump 24 When the pump, valve and passage units 232, 234 and 236 are in place, the passage unit interconnects the pumping device 238 and the engine valve means 246 in such a manner as to produce a mode of operation which is described in detail in my Patent No. 2,949,857. Consequently, a further description herein is unnecessary.

The pump, valve and passage units 232, 234 and 236 may be installed and removed in much the same way as the passage units 32, 34- and 36. Consequently, no further description in this connection is necessary herein.

interchangeability of Duplex and Single Pumps 22 and 24 As will be apparent from the foregoing, the present invention permits interchanging the duplex and single pumps 22 and 24 very simply without disturbing the bottom hole assembly 79 and the production, supply and return tubings 72, 74 and '76. Initially, when the well has a high productive capacity, the duplex pump 22 may be installed. Later, it the productive capacity of the well falls off sufficiently that further use of the duplex pump 22 is not warranted, the pump, valve and passage units 32, 34 and 36 thereof may be run out and the pump, valve and passage units 232, 234 and 236 of the single pump 24 run in. This change of pump types can be effected with a minimum down time, which is an important feature of the invention. Also, irrespective of which of the pumps 22 and 24 is in use, the corresponding pump and valve units may be run in and out readily as required for normal maintenance purposes. Since the passage units 36 and 236 have no moving parts subject to wear, the particular one in use will ordinarily not be removed from the well until such time as a change in pump type is desired.

Duplex Pump 26 The duplex pump 26, illustrated in FIGS. 4 to 14 of the drawings, is merely an actual physical embodiment of the semidiagrammatically illustrated duplex pump 22. Consequently, the same reference characters will be utilized in connection with the duplex pump 26, and this description of the pump 26 will be restricted to certain novel structural features thereof.

One feature of the present invention is that it permits making up the duplex pump 26 from what might be termed standard units normally used for single-pump operation. Thus, the duplex pump unit 3 2 may be formed very simply by coupling, erg. threading, together two standard pumping devices each normally used individually. All that is necessary is to substitute the annular plugs 96a and 96b shown in FIGS. 1 and 2 of the drawings for the annular plugs with which the standard pumping devices are ordinarily equipped, and to substitute the pistons 84a and 3411 having the single control grooves 143a l2 and 14811 therein. Thus, the present invention requires stocking only a minimum number of pump-unit parts.

Similarly, What might be termed standard engine valves, each normally used alone, may be employed as the two engine valve means 112a and 112i; and suitably coupled together to fonrn the valve unit 34. Referring to FIGS. 13 and 14 of the drawings, two standard engine valves are used for the respective engine valve means 112 and 11-2!) and are coup-led together by a rod 279 threadedly connected thereto. This rod is provided with a suitable passage 2'72 therein to connect the upper end of the engine valve means 1121b to the annular clearance 126. Threadediy connected to the lower end of the engine valve means 1115b is a rod 274 which is engageable with the valve-unit seat 54. Thus, the valve unit 34 may be made up very simply from standard parts, except for the two rods 27% and 274.

The passage unit 36, as previously described, comprises the two passaged heads 13%;: and 13012 interconnected by the tubes 136, 138, 149 and 142 and spaced apart by the sleeve a134, the two heads being identical, but reversed in position. The heads 13% and 1313b are connected to the sleeve 134 and to the tubes 136, 138, 1 .9 and 142 in any suitable manner, as by soldering. As shown in FIG. 8 of the drawings, the sleeve 1 34 is preferably provided with a vent port 278 to admit into the sleeve externally of the tubes 136, 138, '14:? and 142 therein the pressure in the return tubing 76, by way of the annular clearance 164 and the passage 162a (FIG. '1). This has the effect of preventing collapse of the sleeve 134 and of at least partially balancing the pressures in the tubes 136, 138, 14! and 14-2.

In the construction shown in FIG. 8 of the drawings, the passage-unit head 13% has threaded ly connected thereto a depending rod 280 which forms the lower end of the passage unit 36 and which is engageable with the passageuni-t seat 56.

Considering the bottom hole assembly '76 in more detail, it is, as previously indicated, formed of separate pump-unit, valve-unit and passage-unit housings 62, 64 and 66 to which the production, supply and return tubings 72, 74 and 76 are connected. More particularly, the housings 62, 6'4 and 66 respectively include upper shoes 282, 284 and 286 (FIGS. 4 and 5) in laterally abutting relation, intermediate shoes 292, 294 and 2% (FIGS. 4, 6 and 7) in laterally abutting relation, and lower shoes 302, 3%4 and 3&6 (FIGS. 4, ll and 12) in laterally abutting relation. The shoes 282, 2&4 and 286 are connected to the lower ends or the production, supply and return tubin-gs 72, 74 and 76, respectively. The shoes 292, 2% and 296 are connected to the shoes 232, 284 and 1285, respectively, by tubes 3-12, 314 and 316 (FIGS. 4 and 7). Similarly, the shoes 392, 3414 and 306 are connected to the shoes 292, 294 and 296, respectively, by tubes 3.22, 324 and 32% (FIGS. 4, 7 and 12).

The portions of the passages of the hereinbefore-described passage system which are formed in the bottom hole assembly 76 are, in the actual physical embodiment 26, formed in the various shoes 282, 284-, 2256, 292, 294, 296, 382, 394 and 3%. The sealing collars 98a and $35 associated with the pump unit 32 are carried by the respective pump unit shoes 28-2 and 292, the sealing collars 118a and 113b associated with the valve unit 34 are carried by the respective valve-unit shoes 284 and 294, and the sealing collars 132a and 1321) associated with the passage unit 36 are carried by the respective passageunit shoes 286 and 296.

The foregoing system of laterally abutting shoes provides a simple way of fonming and registering various portions of those parts of the passages of the passage system 120 which are located in the bottom hole assembly '70 itself, which is an important feature of the invention. Another important feature is that the various sets of shoes are so interlocked as to provide and maintain the desired registry of the corresponding passage portions. The shoes 13 282, .236, the shoes 292 294 and 296, and the shoes 3&2, 3&4 and 366 are interlocked in laterally abutting re lation in the same Way. Consequently, only the laterally abutting, interlocked relation between the shoes 292, 294 and 296 will be considered.

Rcfenring to FIGS. 6 and 7 of the drawings, the valveunit and passage-unit shoes 2'94 and 26 laterally abut each other and laterally abut the pump-unit shoe 292. The shoes 294 and 2% are interlocked with the shoe 292 by a tongue and groove means comprising an undercut, preferably dovetail, groove 33s? in the pump-unit shoe 2% and a complementary tongue 3-32 formed half on the valve unit shoe 2.94 and half on the passage-unit shoe 296. The pump-unit shoe 292 is provided with a removable portion or strip 334 which forms one side of the undercut groove 33% and which is secured by screws 336. Thus, with the strip 384 removed, the shoes 292, 294 and 296 may be assembled very readily, the strip 334 then being secured to the shoe 292 by means of the screws 336 to interlock the three shoes together in a positive manner.

The valve-unit and passage-unit shoes 2-94 and 2% are also secured to the pump-unit shoe 292 by screws 338 extending through the shoes 294 and 2% at the abutting surfaces thereof and threaded into the shoe 292. The screws 338 are visible in FIGS. 5 and 7 of the drawings, and a similar, unnumbered, screw for securing the shoes 3434 and 3% to the shoe 392 appears in FIG. 11 of the drawings.

In order to vertically register the shoes 282, 2-84 and 286, the shoes 292, 294 and 2%, and the shoes 382, 3 54- and 386, propenly, the interconnecting tubes 312, 31 4 and 316 :and the interconnecting tubes 322., 324 and 326 may be adjusted as to length in the manner fully disclosed in my Patent No. 2,910,945, granted November 3, 1959.

CONCLUSION .lthough exemplary embodiments of the present invention have been disclosed herein for purposes of illustration, it will be understood that various changes, modifications and substitutions may be incorporated in such embodiments without departing from the spirit of the invention as defined by the claims which follow.

I claim:

1. in a fluid operated pump system for a well, the combination of:

(a) a bottom hole assembly in the well;

(b) a fluid operated pump unit in said bottom hole assembly;

(c) a fluid operated engine valve unit in said bottom hole assembly and spaced from said pump unit for controlling said pump unit;

(a') a passage unit in said bottom hole assembly, and spaced from said pump unit and said engine valve unit, for interconnecting said pump unit and said engine valve unit in fluid communication; and

(e) said pump unit, said engine valve unit and said passage unit being independently installable in and removable from said bottom hole assembly.

2. In a fluid operated pump system for a well, the

combination of:

(a) a bottom hole assembly in the well;

(b) a fluid operated pump unit in said bottom hole assembly;

(0) a fluid opera-ted engine valve unit in said bottom hole assembly alongside said pump unit for controlling said pump unit;

(d) a passage unit in said bottom hole assembly, alongside said pump unit and said engine valve unit, for interconnecting said pump unit and said engine valve unit in fluid communication; and

(e) means for installing said pump unit, said engine valve unit and said passage unit in and for removing them from said bottom hole assembly independently of each other.

3. In a fluid operated pump system for a well, the combination of:

(a) a fluid operated pump unit located in the well and having therein fluid operated engine means and pump means actuable by said engine means;

(b) an engine valve unit located in the well and spaced from said pump unit and having there-in fluid operated engine valve means for controlling the operation of said engine means;

(0) a passage unit located in the well and spaced from said pump unit and said engine valve unit and having therein passage means adopted to interconnect said engine valve means and said engine means in fluid communication;

(d) housing means in the well for said pump unit, said engine valve unit and said passage unit, and having therein passage means connecting said passage means of said passage unit to said engine valve means and said engine means; and

(2) said pump unit, said engine valve unit and said passage unit being independently installable in and removable from said housing means.

4. In a fluid operated pump system for a well, the

combination of:

(a) fluid operated pump unit located in the Well and having therein fluid operated engine means and pump means actualble by said engine means;

(b) an engine valve unit located in the well alongside said pump unit and having therein fluid operated engine valve means for controlling the operation of said engine means;

(0) a passage unit located in the Well alongside said pump unit and said engine valve unit and having therein passage means adopted to interconnect said engine valve means and said engine means in fluid communication;

(d) housing means in the well for said pump unit, said engine valve unit and said passage unit, and having therein passage means connecting said passage means of said passage unit to said engine valve means and said engine means; and

(e) means for installing said pump unit, said engine valve unit and said passage unit in and for removing them from said housing means independently of each other.

5. In a fluid operated free pump system for a well, the

combination of:

(a) supply, return and production tubings set in the well in side-by-side relation;

(b) a bottom hole assembly connected to the lower ends of said tubings and provided with pump-unit, valve-unit and passage-unit chambers aligned with and communicating with said production, supply and return tubings;

(c) a fluid operated pump unit movable between said pump-unit chamber and the surface through the said tubing with which said pump-unit chamber is aligned;

(d) a fluid operated engine valve unit for controlling said pump unit movable between said valve-unit chamber and the surfiace through the said tubing with which said valve-unit chamber is aligned; and

(e) a passage unit, movable between said passage-unit chamber and the surface through the said tubing with which said passage-unit chamber is aligned, for interconnecting said engine valve unit and said pump unit in fluid communication when said units are in their respective chambers.

6. In a fluid operated free pump system for a well,

the combination of:

(a) supply, return and production tubings set in the Well in side-by-side relation;

(b) a bottom hole assembly connected to the lower ends of said tubings and provided with pump-unit, valve-unit and passage-unit chambers respectively aligned with and communicating with said production, supply and return tubings;

(c) a fluid operated pump unit movable between said pump-unit chamber and the surface through said production tubing;

(d) a fluid operated engine valve unit for controlling said pump unit movable between said valve-unit chamber and the surface through said supply tubing; an

(e) a passage unit, movable between said passage-unit chamber and the surfiace through said return tubmg, for interconnecting said engine valve unit and said pump unit in fluid communication when said units are in their respective chambers.

7. In a fluid operated pump system for a well, the

combination of:

(a) a bottom hole assembly in the well;

(b) a pump unit located in said bottom hole assembly and including two fluid operated pumping devices each having therein fluid operated engine means and pump means aetuable by said engine means;

() an engine valve unit located in said bottom h-ole assembly and spaced from said pump uni-t and hlav- 1ng therein two fluid operated engine valve means for controlling the operation of said engine means, respectively;

(d) a passage unit located in said bottom hole assembly and spaced from said pump unit and said engine valve unit and having therein passage means interconnecting said engine valve means and said engine means in fluid communication; and

(e) said pump unit, said engine valve unit and said passage unit being independently installable in and removable from said bottom hole assembly.

8. in a fluid operated pump system for a well, the

combination of:

(a) a bottom hole assembly in the well;

(b) a pump unit located in said bottom hole assembly and including two axially aligned, fluid operated pumping devices each having therein fluid operated engine means and pump means actuable by said engine means;

{c) an engine valve unit located in said bottom hole assembly alongside said pump unit and having therein two axially aligned, fluid operated engine valve means for controlling the operation of said engine means, respectively;

(d) a passage unit locate in said bottom hole assembly alongside said pump unit and said engine valve unit and having therein passage means interconnecting said engine valve means and said engine means in fluid communication; and

((2) said pump unit, said engine valve unit and said passage unit being independently installable in and removable from said bottom hole assembly.

9. in a fluid operated pump system for a Well, the

combination of:

(a) a pump unit located in the well and including two axially aligned, fluid operated pumping devices each having therein fluid operated engine means and pump means actuable by said engine means;

(b) an engine valve unit located in the well alongside :said pump unit and having therein two axially aligned, fluid operated engine valve means for controliing the operation of said engine means, respective y;

(c) a passage unit located in the well alongside said pump unit and said engine valve unit and having therein passage means interconnecting said engine valve means and said engine means in fluid communication;

((1) said passage unit including two axially aligned, passaged heads respectively alongside said engine means and respectively alongside said engine valve means;

(2) a sleeve interconnecting said heads and spacing same apart;

(f) a plurality of tubes in said sleeve and respectively interconnecting passages in said heads; and

'g) said pump unit, said engine valve unit and said passage unit being independently installable in and removable from the well.

10. In a fluid operated tree pump system for a well,

the combination of:

(a) supply, return and production tubings set in the Well in side-by-side relation;

([2) a bottom hole assembly connected to the lower ends of said tubings and provided with pump-unit, valve-unit and passage-unit chambers aligned with and communicating with said production, supply and return tubings;

(c) said pump-unit, valve-unit and passage-unit chambers respectively being formed in pump-unit, valveunit and passage-unit housings which respectively include laterally abutting pump-unit, valve-unit and passage-unit shoes;

(05) means interlocking said shoes together in laterally abutting relation;

(e) a fluid operated pump unit movable between said pump-unit chamber and the surface through the said tubing with which said pump-unit chamber is aligned;

(f) a fluid operated engine valve unit for controlling said pump unit movable between said valve-unit chamber and the surface through the said tubing with which said valve-unit chamber is aligned; and

(g) a passage unit, movable between said passage-unit chamber and the surface through the said tubing with which said passage-unit chamber is aligned, for interconnecting said engine valve unit and said pump unit in fluid communication when said units are in their respective chambers.

11. In a fluid operated free pump system for a well,

the combination of:

(a) supply, return and production tubings set in the well in side-by-side relation;

(b) a bottom hole assembly connected to the lower ends of said tubings and provided with pump-unit, valve-unit and passage-unit chambers aligned with and communicating with said production, supply and return tubings;

(c) said pump-unit, valve-unit and passageunit chambers respectively being formed in pump-unit, valveunit and passage-unit housings which respectively include laterally abutting pump-unit, valve-unit and passage-unit shoes;

(d) dovetail means inter-locking said shoes together in laterally abutting relation;

(e) a fluid operated pump unit movable between said pump-unit chamber and the surface through the said tubing with which said pump-unit chamber is aligned;

(f) a fluid operated engine valve unit for controlling said pump unit movable between said valve-unit chamber and the surface through the said tubing with which said valve-unit chamber is aligned; and

(g) a passage unit, movable between said passage-unit chamber and the surface through the said return tubing with which said passage-unit chamber is aligned, for interconnecting said engine valve unit and said pump unit in fluid communication when said units are in their respective chambers.

12. In a fluid operated free pump system for a well,

the combination of:

'(a) supply, return and production tubings set in the well in side-by-side relation;

(b) a bottom hole assembly connected to the lower ends of said tubings and provided with pump-unit, valve-unit annd passage-unit chambers aligned with and communicating with said production, supply and return tubings;

(c) said pump-unit, valve-unit and passageamit chambers respectively being formed in pump-unit, valve- :unit and passage-unit housings which respectively include laterally abutting pump-unit, valve-unit and passage-unit shoes;

(d) dovetail means connecting said valve-unit and passage-unit shoes to said pump-unit shoe in laterally abutting, interlocked relation, said dovetail means including a dovetail groove formed in said pumpunit shoe and receiving said valve-unit and passageunit shoes therein in laterally abutting, side-by-side relation;

(e) a fluid operated pump unit movable between said pump-unit chamber and the surface through the said tubing with which said pump-unit chamber is aligned;

(f) a fluid operated engine valve unit for controlling said pump unit movable between said valve-unit chamber and the surface through the said tubing with which said valve-unit chamber is aligned; and

(g) a passage unit, movable between said passage unit chamber and the surface through the said tubing with which said passage-unit chamber is aligned, for interconnecting said engine valve unit and said pump unit in fluid communication when said units are in their respective chambers.

13. In a fluid operated free pump system for a Well,

the combination of:

(a) supply, return and production tubings set in the well in side-by-side relation;

(b) a bottom hole assembly connected to the lower ends of said tubings and provided with pump-unit, valve-unit and passage-unit chambers aligned with and communicating with said production, supply and return tubings;

(c) said pump-unit, valve-unit and passage-unit chambers respectively being formed in pump-unit, valveunit and passage-unit housings which respectively include laterally abutting pump-unit, valve-unit and passage-unit shoes;

(:1) dovetail means connecting said valve-unit and passage-unit shoes to said pump-unit shoe in laterally abutting, interlocked relation, said dovetail means including a dovetail groove formed in said pumpunit shoe and receiving said valve-unit and passageunit shoes therein in laterally abutting, side-by-side relation;

(2) said pump-unit shoe including a removable portion having thereon one side Wall of said dovetail groove;

(1) a fluid operated pump unit movable between said pump-unit chamber and the surface through the said tubing with which said pump-unit chamber is aligned;

(g) a fluid operated engine valve unit for controlling said pump unit movable between said valve-unit chamber and the surface through the said tubing with which said valve-unit chamber is aligned; and

(h) a passage unit, movable between said passageunit chamber and the surface through the said tubing with which said passage-unit chamber is aligned, for interconnecting said engine valve unit and said pump unit in fluid communication when said units are in their respective chambers.

14. A bottom hole assembly for a fluid operated pump system including:

(a) two laterally abutting, tubular shoe means one adapted to receive therein at least a portion of a fluid operated pump unit and the other adapted to receive therein at least a portion of at least one other unit cooperable with said pump unit; and

(b) interlocking tongue and groove means, including an undercut groove in one of said shoe means and a complementary tongue on the other, for securing said shoe means together in laterally abutting relation.

15. A bottom hole assembly for a fluid operated pump system including:

(a) two laterally abutting, tubular shoe means one adapted to receive therein at least a portion of a fluid operated pump unit and the other adapted to receive therein at least a portion of at least one other unit cooperable with said pump unit;

(b) interlocking tongue and groove means, including an undercut groove in one of said shoe means and a complementary tongue on the other, for securing said shoe means together in laterally abutting relation; and

(c) said one shoe means including a removable portion having thereon one side wall of said undercut groove.

16. In an apparatus for interconnecting in fluid communication a fluid operated pump unit and a fluid operated engine valve unit when said pump unit and said engine valve unit are in a pump-unit chamber and a valveunit chamber, respectively, in a bottom hole assembly set in a Well, said bottom hole assembly having passages therein communicating with said pump-unit and valveunit chambers, the combination of:

(a) a passage-unit chamber in said bottom hole assembly and communicating with at least some of said passages therein; and

(b) a passage unit in said passage-unit chamber and having passages therein communicating with at least some of those of said passages in said bottom hole assembly which communicate with said passage-unit chamber.

17. In an apparatus for interconnecting in fluid communication a fluid operated pump unit and a fluid operated engine valve unit when said pump unit and said engine valve unit are in a pump-unit chamber and a valve-unit chamber, respectively, in a bottom hole assembly set in a well, said pump unit and said valve unit being movable into and out of said pump-unit and valveunit chambers, respectively, through pump-unit and valveunit tubings connected to said bottom hole assembly in alignment with said pump-unit and valve-unit chambers, respectively, said bottom hole assembly having passages therein communicating with said pump-unit and valveunit chambers, the combination of:

(a) a passage-unit chamber in said bottom hole assembly and communicating with at least some of said passages therein;

(b) a passage unit in said passage-unit chamber and having passages therein communicating with at least some of those of said passages in said bottom hole assembly which communicate with said passage-unit chamber; and

(c) a passage-unit tubing which is connected to said bottom hole assembly in alignment With said passageunit chamber and through which said passage unit is movable into and out of said passage-unit chamber.

18. In a fluid operated pump system for a well, the

combination of (a) a system of tubings set in the well;

(b) a bottom hole assembly connected to the lower end of said tubing system and adapted to receive therein a fluid operated pump unit and a fluid operated engine valve unit for controlling the pump unit;

(0) a passage unit receivable in said bottom hole assembly for interconnecting the engine valve unit and the pump unit in fluid communication when said passage unit, the engine valve unit and the pump unit are installed in the bottom hole assembly; and

(d) means for installing said passage unit in and for removing it from said bottom hole assembly.

19. In a fluid operated pump system for a well, the

combination of:

(a) a system of tubings set in the Well;

(b) a bottom hole assembly connected to the lower end of said tubing system and adapted to receive 19 20 therein a fluid operated pump unit and a fluid op (d) means for installing said passage unit in and for erated engine valve unit for controlling the pump removing it from said bottom hole assembly through unit; one of the tubings of said tubing system. (c) a passage unit receivable in said bottom hole assembly for interconnecting the engine valve unit 5 References Cited in the file Of this Patent and the pump unit in fluid communication when said UNITED STATES PATENTS pa g unit, h ng valve ni and the p mp 2,949,857 Cobefly Aug 23 1960 unit are installed in the bottom hole assembly; and 

1. IN A FLUID OPERATED PUMP SYSTEM FOR A WELL, THE COMBINATION OF: (A) A BOTTOM HOLE ASSEMBLY IN THE WELL; (B) A FLUID OPERATED PUMP UNIT IN SAID BOTTOM HOLE ASSEMBLY; (C) A FLUID OPERATED ENGINE VALVE UNIT IN SAID BOTTOM HOLE ASSEMBLY AND SPACED FROM SAID PUMP UNIT FOR CONTROLLING SAID PUMP UNIT; (D) A PASSAGE UNIT IN SAID BOTTOM HOLE ASSEMBLY, AND SPACED FROM SAID PUMP UNIT AND SAID ENGINE VALVE UNIT, FOR INTERCONNECTING SAID PUMP UNIT AND SAID ENGINE VALVE UNIT IN FLUID COMMUNICATION; AND (E) SAID PUMP UNIT, SAID ENGINE VALVE UNIT AND SAID PASSAGE UNIT BEING INDEPENDENTLY INSTALLABLE IN AND REMOVABLE FROM SAID BOTTOM HOLE ASSEMBLY. 